The chapter on terrorism tells of the torrent of data available from the FBI, CIA, publicly available databases, as well as monitored phone calls (some legally, many not), Web site visits, transportation records, tax filings, ubiquitous cameras and who knows what else. This informational tsunami rushes past the National Security Agency's numerati, who attempt to pan nuggets out of the torrent.
Baker duly notes the danger of false positives in this endeavor. With ever more pieces of information and ever more superficially suspicious interconnections among them, the vast majority of the people picked out will likely be innocent. Note the million names or so on the airline watch list and appreciate the continuing importance of habeas corpus.
Baker mentions other ethical issues, too. What if a profile constructed from all available data had a certain probability of picking out a prospective pedophile. Would a school, for example, be liable if it uses or fails to use this information in the hiring of applicants? What if the probability were 25 percent? Or 90 percent?
More technical problems arise when data mining pictures, graphics and videos. These play an increasingly salient role in a less print-oriented culture and political environment, yet they're hard to search through and classify. If interested parties could quickly search YouTube, for example, and locate blatantly inconsistent statements by politicians, that would make lying (alright, spinning) less attractive.
Since mathematics is a somewhat imperialistic discipline, the same software tools and data mining techniques useful in one domain apply in many disparate realms, as well. The ideas employed to find terrorists' messages and their senders are also used to find e-mail spam and its origins, to find dangerous molecules in our blood, to find suitable fits between workers and jobs, or to find potentially compatible mates.
The connection among these various tasks is often nominal, consisting in no more than the fact that they all use similar mathematical tools.
Despite the slightly sinister, Svengali-like sound to "the numerati," Baker writes near the end of the book that these folks and their mathematical tricks will, for the most part, make our lives easier (unless we're trying to hide our hangover from the snooping floor).
Far from being controlling, they will allow us to be more fully who we choose to be. Just as we all drive cars without understanding what a carburetor does, we'll all use these software tools without understanding how dynamic optimization works.
John Allen Paulos, a professor of mathematics at Temple University, is the author of the best-sellers "Innumeracy" and "A Mathematician Reads the Newspaper," as well as of the just-released "Irreligion: A Mathematician Explains Why The Arguments for God Just Don't Add Up ". His "Who's Counting?" column on ABCNews.com appears the first weekend of every month.